On 19 November 2008, Lee became the seventh Korean player to earn 100 caps in a World Cup qualifier against Saudi Arabia.

An impressive player in the league, Lee could play for the South Korean national team in the 2002 FIFA World Cup.

He followed Guus Hiddink and teammate Park Ji-sung into PSV Eindhoven after finishing the World Cup in fourth place.

Lee and his compatriot Park were instrumental in PSV Eindhoven's run to the 2005 UEFA Champions League semi-final, although, to their disappointment, they were knocked out by Milan.

In the beginning of 2006–07 season, Lee moved to right full-back due to Benoît Assou-Ekotto's impressive pre-season performance and an injury to regular right-back Paul Stalteri.

Lee then faced increased competition when Tottenham signed French defender Pascal Chimbonda on the final day of the transfer period.

Lee also suffered a knee injury and in August 2006, Tottenham offered his rights to Roma of Italy's Serie A, but he backed out at the last minute for "personal reasons".

He said that moving to Roma would have been great for him in terms of football alone but he decided against it for personal reasons that he would not reveal, despite being pressed for answers by 50 attending reporters.

[4] Lee regained his place in the first team when Assou-Ekotto's form began to falter, most notably in a very poor performance against arch-rivals Arsenal.

[9] He consistently made appearances early in the season, and Borussia Dortmund announced that the period of Lee's contract was extended to two years in December.